Ivory soap is a well-known product that has been widely used since its creation in 1878. The company makes a number of soap products, including liquid dish detergent, which is often mixed with water to make a homemade insecticidal soap spray. The spray, which is effective against a number of common garden pests, is a less-toxic alternative to chemical pesticides and insecticides, because it poses lower risk to people, animals and the environment.

Its Targets

"The Encyclopedia of Entomology," Vol. 4, reports that Ivory liquid dishwashing soap provided consistent results when tested on soft-bodied pests such as mites, thrips and aphids. According to the "Organic Handbook of Natural Insect and Disease Control," insecticidal soap may also kill mealybugs, whiteflies, earwigs, chiggers, scale, fleas and ticks. The solution works by penetrating the cell membranes, which causes the pest to quickly collapse and die.

The Formula

To make insecticidal soap, combine 5 tablespoons of Ivory liquid dishwashing soap with 1 gallon of water. This makes a 2 percent solution, which is suitable for most plants. To keep your plants safe, test the solution on an inconspicuous leaf before spraying the entire plant, then check the leaf in 24 hours. If the plant looks wilted or shows other adverse effects, mix a lighter solution with half as much dishwashing liquid. Don't use a concentration higher than 2 percent because the soap may scorch the foliage.

The Method

Insecticidal soap spray is most effective if you treat plants as soon as you notice pests, while the infestation is light. Spray plants with insecticidal soap spray in early morning or late afternoon or on an overcast day, because the solution may scorch leaves on hot, sunny days. Wet the foliage thoroughly, covering the tops and bottoms of the leaves, because the solution only works when it coats the pests. Because the spray kills on contact, it has little residual effect and must be reapplied every week until the pests are controlled.

About the Author

M.H. Dyer began her writing career as a staff writer at a community newspaper and is now a full-time commercial writer. She writes about a variety of topics, with a focus on sustainable, pesticide- and herbicide-free gardening. She is an Oregon State University Master Gardener and Master Naturalist and holds a Master of Fine Arts in creative nonfiction writing.

Dyer, M.H.. (n.d.). Can You Put Ivory Dish Soap and Water on Plants to Keep Bugs Off? Home Guides | SF Gate. Retrieved from http://homeguides.sfgate.com/can-put-ivory-dish-soap-water-plants-keep-bugs-off-96613.html